The present invention relates to a mulch film for use in agriculture.
The use of mulch films, that is, plastic films spread along the ground and provided with holes for the sowing of seeds or planting of seedlings, is well-established in agriculture. Their purpose is to promote plant growth by ensuring favorable growth conditions, such as enhanced soil temperatures, as well as reliable weed control without need for herbicides. Such influencing of the plant environment is possible by manipulation of absorptive, reflective and transmissible properties of the mulch film.
Such a film is known from European Patent Publication No. 0 398 243, some of the teachings of which are incorporated herein by reference.
While, due to photoselective transmission, the green film according to said publication provides a useful answer to the above-mentioned problems, the subject matter thereof does not address the important problem of effective protection against insects that constitute vectors of various plant diseases and require the application of agrochemicals and/or insect netting. Agrochemicals load the environment and insect nets reduce the crop yield, due to their reduction of the transmission of light
It is thus one of the objects of the present invention to provide a mulch film that not only heats the soil it covers and substantially reduces weed growth, but also acts as a repellent with respect to insects, many of which act as disease vectors, this property being based on photoselective reflection of light.
According to the invention, the above object is achieved by providing a polymeric, multilayer, photoselective mulch film for use in agriculture, comprising at least two layers, an upper layer facing the sky and a lower layer facing the ground, both layers being light-transmissive, wherein said upper layer is of a substantially yellow color and the lower layer is of a substantially blue color, whereby the solar radiation transmitted by said film and reaching the ground is substantially in the green and the far-red range of the solar spectrum, with the green component largely depriving weeds of essential photosynthetically active radiation and the far-red component being absorbed by, and heating, the soil, and whereby the yellow color of the upper layer serves to repel insects liable to act as vectors of plant diseases.
The invention further provides a method of crop cultivation, comprising the steps of providing a multilayer, light-transmissive mulch film, one layer of which is yellow and the other layer of which is blue; spreading said mulch film along the ground with the yellow layer facing the sky and the blue layer facing the ground, and providing suitably spaced holes in said film, or using pre-prepared holes in said film, to sow seeds or plant seedlings.